Ni Mixture Research Articles

The Effect of Nickel Content and Mechanical Activation on Combustion in the 5Ti + 3Si + <i>х</i>Ni System

Intermetallic alloys were synthesized in the 5Ti + 3Si + xNi system by the method of self-propagating high-temperature synthesis (SHS) and mechanosynthesis. The influence of nickel content on the morphology, size and yield of composite particles after mechanical activation (MA) of mixtures was studied. The dependences of the maximum temperatures and combustion rates, phase composition, morphology and elongation of synthesis products on the nickel content for the initial and MA mixtures are studied. Under the conditions of the experiments conducted in this work, combustion process was able to realize and at the same time the samples burned completely at a nickel content of 10 to 60 wt.% in the 5Ti + 3Si + xNi system. After MA, the samples from the 5Ti + 3Si mixture burned to the end, and during the activation of the 5Ti + 3Si + 40% Ni mixture, mechanochemical synthesis occurred. With increasing nickel content combustion temperature decreases, and combustion velocity behaves nonmonotonically, increases the size of composite particles and decreases the yield of the mixture after MA. MA practically did not affect the maximum combustion temperatures of mixtures of 5Ti + 3Si + xNi. A multiple (from 0.7 to 2.9 cm/s) increase in the burning rate of samples from MA mixtures with an increase in the Ni content from 20 to 30 wt. % was recorded. An increase in the nickel content leads to an increase in the content of triple phases and the amount of melt in the synthesis products of mixtures of 5Ti + 3Si + xNi. Shrinkage of product samples increases with increasing nickel content in the initial mixtures. After MA, the shrinkage of the product samples is replaced by their growth. Explanations of the observed dependencies are proposed.

Effects of Cadmium and Nickel Mixtures on Multiple Endpoints of the Microalga Raphidocelis subcapitata.

It is crucial to investigate the effects of mixtures of contaminants on aquatic organisms, because they reflect what occurs in the environment. Cadmium (Cd) and nickel (Ni) are metals that co-occur in aquatic ecosystems, and information is scarce on their joint toxicity to Chlorophyceae using multiple endpoints. We evaluated the effects of isolated and combined Cd and Ni metals on multiple endpoints of the chlorophycean Raphidocelis subcapitata. The results showed that Cd inhibited cell density, increased reactive oxygen species (ROS) production (up to 308% at 0.075 mg L-1 of Cd), chlorophyll a (Chl a) fluorescence (0.050-0.100 mg L-1 of Cd), cell size (0.025-0.100 mg L-1 of Cd), and cell complexity in all concentrations evaluated. Nickel exposure decreased ROS production by up to 25% at 0.25 mg L-1 of Ni and Chl a fluorescence in all concentrations assessed. Cell density and oxygen-evolving complex (initial fluorescence/variable fluorescence [F0/Fv]) were only affected at 0.5 mg L-1 of Ni. In terms of algal growth, mixture toxicity showed antagonism at low doses and synergism at high doses, with a dose level change greater than the median inhibitory concentration. The independent action model and dose-level-dependent deviation best fit our data. Cadmium and Ni mixtures resulted in a significant increase in cell size and cell complexity, as well as changes in ROS production and Chl a fluorescence, and they did not affect the photosynthetic parameters. Environ Toxicol Chem 2024;43:1855-1869. © 2024 SETAC.

Subchronic Exposure to Mixture of Cadmium, Copper, and Nickel Induces Neurobehavioral Deficits and Hippocampal Oxidative Stress of Wistar Rats.

The present study was aimed at evaluating the influence of the subchronic exposure of cadmium (Cd), copper (Cu), and nickel (Ni) mixtures on affective behaviors, memory impairment, and oxidative stress (OS) in the hippocampus. Thirty male Wistar rats were divided into 5 equal groups. Group 1 (control) received a saline solution (NaCl 0.9%). Groups 2, 3, and 4 received Cd (0.25 mg/kg), Cu (0.5 mg/kg), and Ni (0.25 mg/kg), respectively, while group 5 received a Cd, Cu, and Ni mixture through intraperitoneal injections for 2 months. After the exposure period, all rats were submitted to behavioral tests. Subsequently, OS markers and histological changes in the rats' hippocampi were assessed. Results showed that a 2-month exposure to the mixtures of metals (MM) has led to higher anxiety-like and depression-like behaviors and cognitive deficits in rats when compared to the control group and the individual metals. Furthermore, the MM induced heightened OS, evidenced by the rise in lipid peroxidation and nitric oxide levels. These effects were accompanied by a decrease in superoxide dismutase and catalase activities in the hippocampus. The histopathological analysis also supported that MM caused a neuronal loss in the CA3 sub-region. Overall, this study underscores that subchronic exposure to the Cd, Cu, and Ni mixture induces an OS status and histological changes in the hippocampus, with important affective and cognitive behavior variations in rats.

The catalytic activity of copper/nickel supported on mesoporous aluminum catalyst towards cyclohexene epoxidation in continuous reactor

The intent of the study is to attain a high selectivity rate and stable interaction between metals in any heterogeneous catalyst. Cyclohexene is extremely valuable in industrial domains such as the synthesis of perfumes and nylons, and the mesoporous alumina was upstretched with a various ratio of bimetal copper (10%) and nickel (5%, 10%, 15%, and 20%) under wet impregnation procedures by the mesoporous aluminum catalyst. This impregnation of a metal and catalyst was used to assess the highest conversion and selectivity of cyclohexene to cyclohexanol. This catalytic nature was validated by analyzing the crystal structure and size using the X-ray diffraction technique. The functional group is identified using FT-IR (Fourier Transform Infrared Spectroscopy), while the surface area is assessed using BET (Brunauer-Emmet-Teller). HR-TEM (transmission electron microscopy) is used to validate the morphology of catalysts and their surface layers; HR-SEM (Scanning Electron Microscopy) is used to highlight and assess microparticles; and NH3TPD (Temperature-Programmed Desorption) is used to measure the overall acidity of the catalyst. The catalytic performance was proved by the yield achieved by varying parameters such as temperature, pressure, WHSV−1, reaction time, and solvents, which yielded over 98.5% in both cyclohexene conversion and selectivity. In the conversion of the product, H2O2 performs as an oxidant, and acetonitrile serves as a solvent at constant mild conditions of 90 °C and 20 bar pressure. Furthermore, even after seven successive runs with the Al2O3/Cu (10%)-Ni (15%) mixture, remarkable reusability was attained despite a minor decline in cyclohexanol selectivity. The effective impregnation of copper and nickel into supported mesoporous Al2O3 produced a long-lasting, stable hybrid nanostructure with excellent stability and no metal leaching. The current synthesis protocol's advantages and qualities include its efficiency, cost-effectiveness, ecological sustainability, and comfort of synthesis with readily available components.

Nature of the Increase in the Rate of Combustion of a Ti–C Mixture Diluted with an Inert Additive

An original comparative study is performed of the combustion of granular and powder Ti–C and (Ti–C)+20%Ni mixtures with granules of different sizes, while varying titanium particle sizes in a range of 31–142 mm. It is found that the rate of combustion of the (Ti–C)+20%Ni powder mixture is 2–3 times higher than that of a Ti–C mixture, despite the lower temperature of combustion of the former. The results are interpreted in terms of the convective–conductive combustion model and attributed to the inhibitory effect of impurity gases that evolve while heating the component particles ahead of the combustion front. The rate of combustion of the granules’ material is calculated using those of granular mixtures with granule sizes of 0.6–1.7 mm. This rate can be thought of as the rate of combustion of a powder mixture in which the effect of impurity gases is neutralized. It is proposed that the ratio of the rates of combustion of the material inside the granules and the powder mixtures be used as a quantitative measure of the effect impurity gas evolution has on the combustion of powder mixtures.

Novel porous phosphoric acid-based geopolymer foams for adsorption of Pb(II), Cd(II) and Ni(II) mixtures: Behavior and mechanism

In this work, novel porous phosphoric acid activated geopolymer foams (abbreviated as PAG) with open cell structure are synthesized from a simple and effective process. Commercial metakaolin (MK) is used as raw material, hydrogen peroxide solution and Triton X-100 act as pore former and foam-stabilizer agents, respectively. The resultant PAG samples possess macropores around several millimeters and micro-cracks on geopolymer matrix. Different analytical instruments including optical microscope, X-ray diffraction, scanning electron microscopy equipped with energy-dispersive spectroscopy, Fourier transform infrared spectrometer, Brunauer-Emmett-Teller surface area measurement, etc. are applied to analyze the structural evolution. The obtained PAG is tested for heavy metals removal in unitary (Pb, Cd, Ni), binary (Pb–Cd, Pb–Ni, Cd–Ni) and ternary (Pb–Cd–Ni) metal solutions. The effect of pH on the simultaneous removal performance of Pb2+, Cd2+ and Ni2+ by PAG is studied. The maximum removal efficiency of Pb2+, Cd2+ and Ni2+ is achieved at pH = 7, and the selectivity sequences of the three metals adsorbed in ternary (Pb–Cd–Ni) metal solution is Pb2+ (11.99 mg/g)> Ni2+ (6.16 mg/g)> Cd2+(2.81 mg/g). The adsorption mechanisms are heavy metals exchanged with H+ in geopolymer matrix and surface complexation with the abundant –OH groups (Si–OH, P–OH, Al–OH) on PAG. The selectivity sequence can be ascribed to the difference of the hydrated heavy metals' radii. The heavy metals adsorption capacities of acid activated geopolymer foams are higher than that by alkali activated geopolymer monoliths reported in literature, suggesting its high potential application in wastewater treatment.

Combustion Macrokinetics of Granulated (Ti + C)–Ni Mixtures. Impact of Grain Size

Combustion Macrokinetics of Granulated (Ti + C)–Ni Mixtures. Impact of Grain Size

Tuning the reactivity of Al–Ni by fine coating of halogen-containing energetic composites

In this paper, various core-shell structured Al–Ni@ECs composites have been prepared by a spray-drying technique. The involved ECs refer to the energetic composites (ECs) of ammonium perchlorate/nitrocellulose (AP/NC, NA) and polyvinylidene fluoride/hexanitrohexaazaisowurtzitane (PVDF/CL-20, PC). Two Al–Ni mixtures were prepared at atomic ratios of 1:1 and 1:3 and named as Al/Ni and Al/3Ni, respectively. The thermal reactivity and combustion behaviors of Al–Ni@ECs composites have been comprehensively investigated. Results showed that the reactivity and combustion performance of Al–Ni could be enhanced by introducing both NA and PC energetic composites. Among which the Al/Ni@NA composite exhibited higher reactivity and improved combustion performance. The measured flame propagation rate (v = 20.6 mm/s), average combustion wave temperature (Tmax = 1567.0 °C) and maximum temperature rise rate (γt = 1633.6 °C/s) of Al/Ni@NA are higher than that of the Al/Ni (v = 15.8 mm/s, Tmax = 858.0 °C, and γt = 143.5 °C/s). The enhancement in combustion properties could be due to presence of the acidic gaseous products from ECs, which could etch the Al2O3 shell on the surface of Al particles, and make the inner active Al to be easier transported, so that an intimate and faster intermetallic reaction between Al and Ni would be realized. Furthermore, the morphologies and chemical compositions of the condensed combustion products (CCPs) of Al–Ni@ECs composites were found to be different depending on the types of ECs. The compositions of CCPs are dominated with the Al–Ni intermetallics, combining with a trace amount of Al5O6N and Al2O3.

Combustion Macrokinetics of Granulated (Ti+C)-Ni Mixtures. Impact of Grain Size

Combustion Macrokinetics of Granulated (Ti+C)-Ni Mixtures. Impact of Grain Size

Comparison of Performance and Microstructure of Two Kinds of Cold Spray Anticorrosion Composite Coatings on High-strength Steel

Objective to study the performance of Zn/Ni composite coatings and Al/Zn composite coatings, which were deposited by Cold Gas Dynamic Spray. Methods: Those coatings was sprayed by Zn and Ni mixture powder and Al and Zn mixture powder on 300M high-strength steel surface, the SEM images and micro hardness tester analyzed the two kinds coatings’ morphology and microstructure. The corrosion resistance of Zn/Ni coatings can be compare with Al/Zn coatings, which was investigated by neutral salt-spray test and coating furcated test. Results The results indicate that Zn/Ni coatings porosity is 0.8%, it is same as Al/Zn coatings. The micro hardness of Zn/Ni coatings is 70.8HV, which is higher than Al/Zn coatings 61.2HV. However, the salt spray result of Al/Zn coatings can reach 1000h and it can reach 770h even the coatings fails; which is better than Zn/Ni coatings, their salt spray resistance can reach 770h and it can reach 350h when the coatings fails. Conclusion those coatings could both be efficient corrosion resistance coatings on 300M high strength steel surfaces.

Scale-Up Studies for Co/Ni Separations in Intensified Reactors.

In this paper, the effect of the scalability of small-scale devices on the separation of Co(II) from a binary Co(II)/Ni(II) mixture in a nitric acid solution by an organic Cyanex 272/TBP/kerosene (Exxsol D80) phase is studied. In particular, circular channels with diameters of 1, 2, and 3.2 mm are considered. The results were compared against those from a confined impinging-jets (CIJ) cell with a main channel diameter of 3.2 mm. The effects of total flowrate, residence time, Cyanex 272 concentration, and flowrate ratio on the mass transfer performance were investigated. It was found that at increased channel size, the throughputs were also increased but the extraction percentages remained the same. Higher extraction percentages were obtained by using the CIJ configuration at short residence times. However, for longer residence times, the mass transfer coefficients were similar and capillary channels should be preferred over the CIJ because of the ease of separation of the two phases at the end of the unit. The overall mass transfer coefficients ranged between 0.02 and 0.14 s−1 for the capillary channels during plug flow and between 0.05 and 0.45 s−1 for the CIJ cells during dispersed flow.

Spherical NiCu phyllosilicate photocatalysts for hydrogen generation

To enhance the photocatalytic performance of semiconductors, a highly active and durable SiO2@xNiCuPS photocatalyst was evaluated for photocatalytic hydrogen generation. The photocatalyst was prepared by a hydrothermal method using SiO2 spheres, and a 1:1 Cu:Ni mixture (5 and 10 wt%). The reaction gave a highly stable phyllosilicate material with a core@shell structure. The materials were characterized by a range of techniques. DRS data revealed indirect optical transitions at 1.5 eV and 2.75 eV for the SiO2@5NiCuPS and SiO2@10NiCuPS materials. The new photocatalysts were successfully tested for hydrogen generation under visible irradiation to give H2 yields of 184 and 47 μmol g−1. min−1 for SiO2@5NiCuPS and SiO2@10NiCuPS, respectively. The data suggest that the enhanced activity of adding Cu to Ni to form Ni/Cu phyllosilicates is not due to NiCu alloy formation but due to changes in the support morpholohgy brought about by metal-support interactions. The catalysts were stable over 4 repeat reaction cycles.

Predicting the combined toxicity of binary metal mixtures (Cu–Ni and Zn–Ni) to wheat

In order to investigate and model toxicity and interactions between metals in mixtures, inhibition of wheat root elongation in response to additions of single-metals of copper (Cu), zinc (Zn), and nickel (Ni) and of binary mixed-metal combinations of Cu–Ni and Zn–Ni was tested, using water culture experiments under different Mg concentrations and pH values. A biotic ligand model (BLM) of single-metal Cu, Zn, and Ni was established. The results showed that the toxicity of Cu, Zn or Ni in isolation decreased with increasing Mg concentration whereas the effects of pH on Cu, Zn, or Ni toxicity were related not only to free Cu2+, Zn2+, and Ni2+ concentrations, but also to inorganic metal complexes. In binary mixtures, the two metals in the Cu–Ni mixture showed a weakly antagonistic effect, whereas the two metals in the Zn–Ni mixture showed greater antagonism. Using data from single-metal Cu, Zn, and Ni BLMs, combined with the toxicity index and the overall amounts of metal ions bound to the biotic ligands, one simple model was developed. This model consisted of the toxic unit (TUM, no competition included) and two extended BLMs, BLM-TUf (f as a function of TU, including competition between Mg2+ and metal ions) and BLM-fmix (including the competition between Mg2+ and metal ions, as well as between free metal ions). They were then used to predict the joint toxicity of Cu–Ni and Zn–Ni binary mixtures to wheat. Both of the extended BLMs could provide more accurate predictions of toxic effects of Cu–Ni and Zn–Ni than TUM. BLM-fmix performed best for the Zn–Ni binary mixture (r2 = 0.93; root-mean-square error, RMSE = 9.87). On the other hand, for the Cu–Ni mixture, the predictive effect based on BLM-TUf (r2 = 0.93; RMSE = 9.60) was similar to that of BLM-fmix (r2 = 0.93; RMSE = 9.56). The results provide a theoretical basis for the evaluation and remediation of soils contaminated with mixtures of heavy metals.

Dependence of Combustion Rates and Maximum Synthesis Temperatures on the Initial Sample Temperature for Initial and Activated Ti + Ni Mixtures

In this study, the dependences of the velocities and maximum combustion temperatures on the initial temperature for initial and mechanically activated Ti + Ni mixtures are determined. For activated mixtures, the transition temperatures from the layer-by-layer combustion to the thermal explosion mode are established. The maximum heating temperatures during a thermal explosion are determined. Observations were made of changes in the appearance and phase composition of burnt samples at different initial temperatures and during the transition from the combustion mode to the thermal explosion mode. It was found that in the case of the initial mixture, in the entire investigated range of initial temperatures, combustion occurs with the formation of a liquid phase in the layer-by-layer combustion mode. In the case of activated mixtures, a solid-phase synthesis mode is realized both in the combustion mode and in the thermal explosion mode.

Mechanoactivated SHS in the Ti–Ni System: Influence of Preheating Temperature

Product composition and combustion parameters for non-activated and mechanically activated Ti–Ni mixtures were explored as a function of preheating temperature T0. Upon an increase in T0, frontal combustion of activated blends was found to change to a mode of thermal explosion at T0 around 190°С. Frontal combustion of non-activated blends was accompanied by local melting over the entire range of T0. Our results may turn helpful in theoretical modeling of SHS reactions.

Investigation on High Temperature Mechanical Behaviors of TiC-γ′ Reinforced Ni Composite

A duplex TiC and γ′-Ni3(Al,Ti) reinforced nickel composite was fabricated through hot-press sintering a 30 vol% Ti2AlC–Ni mixtures followed by thermal treatment method. Detailed microstructural detection was performed by adopting the route of high-resolution transmission electron microscopy. In situ generated submicron TiC particulate and nanosized L12-γ′ were homogeneously distributed in a fcc γ-Ni matrix. The high temperature tensile and compression behaviors of the TiC-γ′/Ni composites were evaluated in the temperature range of 25–800 °C. The results indicated that ultimate tensile and compression properties exhibited the dependence of temperatures. The tensile properties of the composite determined at 600 °C was 945 MPa, decreasing by 28.1% and 23.0% for elongation, compared to those of measured at room temperature (UTS = 1305 MPa, elongation = 5.35%). However, the yield strength exhibited the temperature independent until to 600 °C. The yield strength of the TiC-γ′/Ni composite are comparable with conventional superalloy under 600 °C, proving that TiC and γ′ particles constitute efficient reinforcements for Ni matrix according to thermal expansion dislocations strengthening, load-transfer and coherent strengthening mechanisms. The monotonic temperature dependence of yield strength at 600–800 °C indicates that plastic deformation of TiC-γ′/Ni composite follows the thermally activated mechanism. The TiC-γ′/Ni composite exhibited superior mechanical properties both at room and high temperatures, which can be ascribed to the synergistic strengthening effect in term of dislocation density, Orowan, coherent and atomic ordering strengthening mechanisms. The present work reveals the deformation behaviors of in situ TiC-γ′/Ni composite from room to high temperatures, which is critical to predict the failure and thereby optimize the microstructure to further enhance the high temperature properties of TiC-γ′/Ni composite.

Phase Composition and Structure of Titanium Carbide/Nickel Binder Synthesis Products

We have studied the phase composition and structure of titanium carbide with a nickel binder prepared by self-propagating high-temperature synthesis in a cocurrent inert or reactive gas stream using granulated mixtures containing different grades of titanium. The results demonstrate that, unlike in the case of powder mixtures with a loose bulk density, the products of combustion of a granulated Ti + C + 25% Ni mixture in flowing nitrogen or without it retain their structure and granule size and can readily be ground into powder. In the case of the powder mixture both in a flowing gas and without it and in the case of the granulated mixture in flowing argon, the combustion products have the form of unbreakable sinter cakes, independent of the grade of titanium. Microstructural analysis of the combustion products points to spontaneous dispersion of the titanium particles surrounded by the nickel binder, independent of the starting mixture (granules or powder with a loose bulk density). Moreover, the phase composition of the synthesis products depends on the size and morphology of the titanium particles. In the case of PTM titanium, the final synthesis product consists of titanium carbide and nickel phases. After the combustion of mixtures based on PTM-1 titanium powder or a 50% PTM + 50% PTM-1 mixture, the final product consists of TiC, Ni, and TixNiy intermetallic phases. Synthesis in flowing nitrogen has been shown to change the phase composition of the combustion products of the mixtures based on PTM-1 titanium powder and a 50% PTM + 50% PTM-1 mixture, causing the intermetallic phases to disappear. To account for the combustion behavior of the mixtures, we have proposed a two-step mechanism of interaction in the Ti + C + 25% Ni system.

Dependences of the Burning Rate and Phase Composition of Condensed Products of a Ti + Ni Mixture on the Mechanical Activation Time

A method of preliminary mechanical activation is used to implement the combustion of a Ti + Ni mixture, which does not burn at room temperature. The dependences of the burning rate, maximal temperature of combustion, and elongation of samples on the mechanical activation time of the Ti + Ni powder mixture are described for the first time. Moreover, the microstructure and phase composition of activated mixtures of their combustion products are studied. The mechanical activation time (9 min) during which the burning rate of the mixture and the content of the main phase (TiNi intermetallide) are maximal in the combustion products is experimentally determined. In these conditions, the combustion propagates within a narrow zone—the maximal temperature corresponds to that in the combustion front.

Recovery of metals from waste nickel-metal hydride batteries using multifunctional Diphonix resin

In this study, Diphonix resin containing sulfonic, diphosphonic and carboxylic groups was used to evaluate the adsorption capacity of metal ions contained in the nickel-metal hydride batteries (Ni-MH). This type of ion exchanger can be considered as the multifunctional material having great affinity to many metal ions. Using Diphonix resin adsorption process was carried out for La(III) and Ni(II) ions to characterize kinetic, adsorption and thermodynamic parameters. Preliminary studies of the Nd(III), Ce(III), La(III), Fe(III), Co(II), Ni(II), Cu(II) and Zn(II) metal ions mixture were also performed. The best results of adsorption studies were obtained using 0.2 M HNO3. Diphonix resin exhibits especially good adsorptive properties with respect to rare earth element ions (adsorption efficiency of about 100%) in comparison with the heavy metal ions in the second oxidation state (about 50% or below). The series of affinity of the resin for the studied ions can be presented as follows: La(III) > Fe(III) > Nd(III) > Ce(III) > Cu(II) > Zn(II) > Co(II) > Ni(II). The obtained results confirmed the possibility of further use of the resin for the recovery and separation of rare earth elements from solutions after Ni-MH batteries leaching.

Dependences of the Burning Rate and Phase Composition of Condensed Products of a Ti + Ni Mixture on the Mechanical Activation Time

Dependences of the Burning Rate and Phase Composition of Condensed Products of a Ti + Ni Mixture on the Mechanical Activation Time